Bittman R, Clejan S, Robinson B P, Witzke N M
Biochemistry. 1985 Mar 12;24(6):1403-9. doi: 10.1021/bi00327a018.
Mono- and dipalmitoylphosphatidylethanolamine derivatives have been synthesized and used to evaluate the role of cross-links between the amino groups of two phospholipid molecules in the rate of cholesterol movement between membranes. Incorporation of the cross-linked phospholipids into small unilamellar vesicles (the donor species) decreased the rate of spontaneous cholesterol exchange with acceptor membranes (small unilamellar vesicles or Mycoplasma gallisepticum cells). These results suggest that the cross-linking of aminophospholipids by reactive intermediates, which may be one of the degenerative transformations associated with peroxidation of unsaturated lipids and cellular aging, can inhibit cholesterol exchangeability in biological membranes. The rates of spontaneous [14C]cholesterol and protein-mediated 14C-labeled phospholipid exchange from diamide-treated mycoplasma and erythrocyte membranes have also been measured. The formation of extensive disulfide bonds in the membrane proteins of M. gallisepticum enhanced the 14C-labeled phospholipid exchange rate but did not affect the rate of [14C]cholesterol exchange. The rates of radiolabeled cholesterol and phospholipid exchange between erythrocyte ghosts and vesicles were both enhanced (but to different extents) when ghosts were treated with diamide. These observations suggest that diamide-induced oxidative cross-linking of sulfhydryl groups in membrane proteins does not lead to random defects in the lipid domain.
已合成单棕榈酰磷脂酰乙醇胺和二棕榈酰磷脂酰乙醇胺衍生物，并用于评估两个磷脂分子氨基之间的交联在膜间胆固醇移动速率中的作用。将交联磷脂掺入小单层囊泡（供体物种）中会降低与受体膜（小单层囊泡或鸡毒支原体细胞）自发胆固醇交换的速率。这些结果表明，由反应性中间体引起的氨基磷脂交联可能是与不饱和脂质过氧化和细胞衰老相关的退化性转变之一，可抑制生物膜中胆固醇的交换能力。还测量了经二酰胺处理的支原体和红细胞膜中自发的[14C]胆固醇和蛋白质介导的14C标记磷脂交换的速率。鸡毒支原体膜蛋白中广泛二硫键的形成提高了14C标记磷脂的交换速率，但不影响[14C]胆固醇的交换速率。当红细胞血影用二酰胺处理时，红细胞血影与囊泡之间放射性标记胆固醇和磷脂的交换速率均增加（但程度不同）。这些观察结果表明，二酰胺诱导的膜蛋白中巯基的氧化交联不会导致脂质结构域出现随机缺陷。
